makefile 库依赖 - 解决循环依赖

Question

我正在尝试在我的 makefile 中构建一个功能，它允许我指定特定库 依赖于

的库列表

这将允许在重建库的依赖项时自动重建该库的依赖项，并将依赖项添加到 link 行。

我在 SO 上问了一个相关问题，根据给定的答案，我想出了以下测试

uniq = $(if ,$(firstword ) $(call uniq,$(filter-out $(firstword ),)))
expand-deps =  $(foreach _,, $(call expand-deps,$($__deps)))
make-dep-list = $(call uniq,$(call expand-deps,))

define make-lib
    $(warning _deps: )
    # capture the list of libraries this library depends on
    _deps = 
endef

define make-bin
    # show the fully expanded list of libraries this binary depends on
    $(warning  dep-list: [$(call make-dep-list,)])
endef

#$(eval $(call make-lib, thread, log utils)) circular-dependency log->thread; thread->log
$(eval $(call make-lib, thread, utils))
$(eval $(call make-lib, log, thread))
$(eval $(call make-lib, order, log))
$(eval $(call make-lib, price, log))
$(eval $(call make-bin, test, order price))

运行上面的 makefile 产生以下结果：

$ make
makefile:15:  thread_deps:  utils
makefile:16:  log_deps:  thread
makefile:17:  order_deps:  log
makefile:18:  price_deps:  log
makefile:19:  test dep-list: [order price log thread utils ]
make: *** No targets.  Stop.

库可能有循环依赖。

举个例子：日志库是多线程的，所以需要线程库。线程库可以发出日志语句，所以需要日志库。

如果我取消注释掉循环依赖的行

$(eval $(call make-lib, thread, log utils))
$(eval $(call make-lib, log, thread))

makefile 将陷入无限循环。

如何让用户指定循环依赖，跳出无限循环？

Answer 1

所以，你的问题是你正在递归地扩展 lib_deps（比方说）。在这样做的同时，您又开始扩展 lib_deps。无限循环（呃，堆栈崩溃）。为了阻止自己，你需要保留一份你已经扩展过的东西的清单。脱离函数式风格并将答案保留在全局 expansion（啊！）中，类似于：

expand-deps = \
  $(foreach _,, \
    $(if $(filter $_,${expansion}),, \
      $(eval expansion += $_)$(call expand-deps,${$__deps})))

make-dep-list = $(eval expansion :=)$(call expand-deps,)${expansion}

define make-lib
  $(warning _deps: )
  # capture the list of libraries this library depends on
  _deps := 
endef

define make-bin
  # show the fully expanded list of libraries this binary depends on
  $(warning  dep-list: [$(call make-dep-list,)])
endef

$(eval $(call make-lib,thread,log utils))#circular-dependency log->thread; thread->log
#$(eval $(call make-lib,thread,utils))
$(eval $(call make-lib,log,thread))
$(eval $(call make-lib,order,log))
$(eval $(call make-lib,price,log))
$(eval $(call make-bin,test,order price))

（作为练习，您可能想以函数式风格重写它，即摆脱全局 $expansion，将其替换为传递的参数。）

makefile 库依赖 - 解决循环依赖

makefile library dependencies - resolve circular dependency

c++

makefile

gnu-make